The present invention concerns a seat, having a backrest with a pressure element.
A known seat of this type (for example, from D.E. 198 06 535 A1) exhibits a number of pressure elements located in both the seat portion as well as the backrest. The pressure elements are chambers that can be filled with a fluid. To enhance the comfort of the occupant, the fluid within each chamber should be adjusted to a pressure that corresponds to the physical characteristics of the person using the seat and his position on the seat. Since, in the case of the known car seat, a large number of chambers are provided that can be filled, individual manual adjustment of the pressure within each chamber is difficult and time-consuming. For this reason, and also to enable the chamber pressures to be adjusted easily and quickly when the seating position of the occupant changes, adjustments in pressure within the various chambers are done automatically in the known seating system, depending on the specific circumstances of the load of each chamber. This type of individual, load-dependent adjustment in the various seat and backrest areas often proves to have drawbacks from an orthopedic viewpoint:
The most important consideration for a healthy sitting posture is the positioning of the spine and pelvis. The manner in which the pelvis is angled affects the curve of the spine in the lumbar area. This is not the only consideration to be taken into account when adjusting the seat, as the anatomical peculiarities of the spine of the individual using the seat must also be considered, so that proper orthopedic adjustment of the seat will be achieved equally well, whether the seat occupant has lordosis, kyphosis, or a straight back. For example, in order to counteract the defective position of the spine in lordosis, the pelvis must be tipped to the rear, and no increase in pressure on the lordotic area of the spine is permissible. On the other hand, the adjustment must be just the opposite for kyphosis. Having a number of uncoordinated adjustment settings, such as those provided by the car seat presumed to be known, fails to take these relations into consideration. In fact, it poses the risk that areas might be adjusted in a manner that is contraindicated.
Proceeding on the basis of this state of the art, the underlying object of the invention is to provide a car seat having pressure elements located in the rear of the seat portion and in the lordotic area of the backrest that can be made adjustable solely in a manner consistent with orthopedic requirements.
By virtue of adjustments to the pressure elements in the rear of the seat portion and in the lordotic area of the backrest being possible only in tandem, a contraindicated adjustment is precluded. Adjustments bringing about less firmness in both pressure elements promote the proper sitting posture for a seat occupant with lordosis, while a firm adjustment of the adjustable areas is suitable for a seat occupant with kyphosis.
Two preferred embodiments are described in detail below with reference to the drawing.